If you find yourself overeating or eating compulsively—from time-to-time or on a regular basis—there may be an explanation for this, but it might not be stress, an emotional response, habit or boredom; it might be fat and sugar.
Addicted to High-Fat Foods
Previous studies have linked a tendency for overindulgence and compulsive eating to consumption of high-fat foods. In 2010, Nature Neuroscience published a study which found, unsurprisingly, rats given unlimited access to high-fat foods, such as bacon, sausage and cheesecake, began to eat copious amounts and ignored the healthful food.
The interesting aspect of the study: The other group of rats who were allowed access to these foods for one hour a day, began to compulsively overeat—consuming 66 percent of their daily food quota during that hour. They had become addicted to the food.
This addiction was so strong that the rats would ignore the threat of an electric shock and continue to eat their high-fat foods.
In their study, the researchers also noticed the rats had a favorite food—cheesecake—which is both high in fat and sugar. The lead researcher noted it may be a combination of fat and sugar triggering this behavior—but a new study suggests sugar is a much more powerful stimulant. Before we get to that; here’s a bit more on addiction and the body’s food-reward system:
Dopamine and Addiction
Researchers know eating triggers release of dopamine (the same release the body experiences with drug use); this feel-good release encourages habitual behavior and stimulates the brain’s food-reward system (more on this system below).
In order for you to feel the dopamine released by your brain, you must have dopamine receptors. People with a low level of receptors will often seek out ways to increase their dopamine release. Some people are born with lower levels receptors; researchers think this may explain why some people are predisposed to overeating. You can also deplete your receptors through habitual behavior (i.e. habitual drug use, overeating, etc.). This begins the deadly cycle of addiction.
It is incredibly difficult to stop the cycle, especially when recovery time is lengthy. The food addiction resulting from high-fat diets observed in rats is so strong, it took two weeks for the depleted dopamine receptors to return to normal, baseline levels. Comparatively, studies with mice have shown a two-day turnaround for cocaine addiction.
The Food-Reward Network
The brain is set up to reward us for external stimuli such as food or a potential partner—this goes back millions of years to our ancient ancestors. Basically, you do something your brain likes and it rewards you with a pleasurable feeling. Stimuli, such as food, lights up certain parts of the brain and researchers can pinpoint what parts of the brain are being affected through imaging machines. (Ever seen the colorful images of the brain? This is called brain imaging or neuroimaging.)
Certain regions of the brain, such as the putamen, insula and rolandic operculum, control the desire for food—this is what is called the food-reward system. The more active these regions are, the more food we crave.
The Sugar Research
Researchers in a study published in The American Journal of Clinical Nutrition in 2013 were surprised to find that sugar lit up the food-reward network more than fat.
The study took 100 healthy adults and had them lay in functional magnetic resonance imaging machines (commonly known as MRI, a kind of neuroimaging). While in the machines, the participants sipped different milkshakes—some high-fat, some high-sugar, some a combination and some with low levels of both fat and sugar. Fascinatingly, the milkshakes with less sugar and less fat only activated the parts of the brain that are related to taste and sensation, and did not affect the brain’s reward system.
The milkshakes with higher amounts of sugar and fat showed stimulation of the brain’s reward system—and the ones with the highest amount of sugar had the greatest impact on this system. This means high-sugar foods may cause the body to crave more food than we should consume—creating major problems with weight and obesity.
We’re All Hard-wired for Food Addiction
One of the problems with overeating, compulsive eating and food addiction is, unlike drugs or alcohol, we need food for survival. As humans, our brains are set up to train us to seek out high-calorie foods to help us to survive, especially during lean times. Now for many humans, especially in wealthier countries, we don’t need this same reward system for high-calorie foods—these foods are readily available.
We’ll continue to learn more about this connection between sugar, fat and overconsumption through new studies; this research will help us learn ways we can fight today’s obesity epidemic and shed light on ways to modify our diets in order to live healthier lives.
In the meanwhile, work on cutting down the amount of sugar in your diet and pay attention to your food triggers. And above all, avoid highly processed foods!